Pressure regulator



D 195] E. J. DILLMAN PRESSURE REGULATOR Filed March 27, 1944 gaz FIG. 2

INVENTOR. W 8M BY 'W/CM M ATTORNEY Patented Dec. 4, 1951 PRESSUREREGULATOR ."Earnest J. Dillman, Detroit, Mich., 'assignor "to DetroitLubricator Company, Detroit, Mich, a

corporation of Michigan Application March 27, 1944, Serial N 0.328252 3Claims. 1

This invention relates to new and useful improvements in refrigeratingapparatus and more particularly to means 'for controlling the loading ofthe refrigerant medium compressor.

An object of "the invention is to provide means to regulate the pressureat which the refrigerant medium is supplied'to the compressor so thatthe quantity of refrigerant medium to be compressed on the compressorworking stroke will be main-' tained within safe limits.

Another object 'is to provide a novel pressure responsive 'valve forlimiting the back pressure to which the compressor is subjected.

The invention consists in the improved construction and combination ofparts to be more fully described hereinafter and the novelty of whichwill be particularly pointed out and dis- 'tinctly'claimed.

In the accompanying :drawings to be taken 'as apart of thisspecification, there are fully and clearly illustrated several preferredembodiments ofthe invention, in which drawings:

Figure l is a diagrammatic view 'of a refriger ating apparatus showingthe cooperative relation of the back pressure controlling valve and 'thecompressor;

Fig. 2 is an enlarged detail view in central vertical section of thevalve of Fig. l and a portion of thecompressor, and

Fig. 3 is a View in vertical central section of another form of backpressure controlling valve.

Referring to the drawings 'by characters of reference, I designatesgenerally a compressor driven by an electric motor 2 and here shown asof the reciprocating piston type, although it will be apparent that theinvention is equally applicable to rotary compressors. The compressorcylinder 3 has an inlet conduit 4 controlled by a :pressure regulatingvalve 5, shown in detail in Fig. 2. The

compressor and its motor and inlet pressure Valve are contained within ahermetically-sealed housing 6, as is well understood in the art, so thatthe motor and compressor will be cooled by the expanded refrigerantmedium. The co'mpressor'cylinder 3 contains the usual reciprocatingpiston 1 having a spring pressed inlet valve 8. The outlet from thecompressor controlled by the usual spring loaded check valve (not-shown)discharges through an outlet conduit or pipe 52 which is sealed in andextends through an opening in'the wall of the housing is. 'Theconduiteconnects to the inlet of a refrigerant medium condenser til which maybecooled by a motor driven ran I I. The outlet of the condenser In lf'eedsthrough an expansion device i 2, :such as the well :kn'own capn atill'a'ry tube connected to 'lhe inlet of an evaporator I3. The outlet ofthe evaporator is connected by a suction conduit or refrigeranti'm'edium return "line pipe 1'4 to the "interior of the housing 6., thedischarge end or the conduit 1'4 being =herme'tically sealed in andthrough the housing wall, :a'sat I 5.

Referring to Fig. 2 th'e inlet conduit 4, which is a hollow tubularmember, is supported and sealed in an opening or aperture I8 through theside wall of the compressor I on the inlet or suction side of thepiston 1. The valve '5 is supported on the free upper end of the conduit4 and: has a cup-like tubular casing H with an "outlet opening 1-8centrally through its base or bottom wall 1'9. The upper end of theconduit '4 extends into and is "sealed in the opening i8 and to the wallI9, as at 2i). Within the casing 1!"! there is a supporting disc 'orplate member 2| having a central aperture therethrough and which issupported and sealed at its periphery 'in an internal annular :channel22 formed in the side wall "of the casing I'l. The supporting member 21has a plurality "of now spaces :or openings 123 1 surrounding itscentral opening for the flow of ref-rigerant me'dium to the outlet I8.Supported and sealed in the central aperture of member 21, there is acup-like end Wall member 24 of anexpansible contractible pressureresponsive member or metal bellows 25. The bellows end Wall 24 forms adash pot housing and has :its base positioned adjacent the outlet 48 anhas sealed therein 'a filling tube 26. The end wall 2 4 is provided withan external shoulder which seats on "the member 21 and forms an internalshoulder to receive the marginal edge portion and thereby support aspring supporting disc and stop member 2:1. The bellows member 25 oneend hermetically sealed as at 28 to the out tur-ned flange 'or rim ofthe end wall 24 and has its other end hermetically sealed as at 29 'to Iahead or end wall plate member 3|]. 'Secured in and through a centralaperture in the head member till there is a valve stem 31 which extendscentrally within the bellows member 25 and through an aperture in thestop member 2-! and terminates within the cylindrical portion of the endwall 2% positioned beneath the stop member 21. This cylindrical end wallportion provides a dash "pot chamber '32 having a piston 33 secured onthe inner "end of the stem 31 and engageable with the stop member 21 'tolimit outward movement of 'th'e'stem 3]. Within the bellows member '25and surrounding the stem 3| there is a helical coil spring' -3'4 whichis new under compression between the bellows head member 30 and. thestop member 21 and which normally tends to hold the bellows member 25expanded to the extent permitted by engagement of the piston 33 with thestop member 21. The bellows member 25 is evacuated of air through thefilling tube 26 and is then charged therethrough with an inert gas andalso with a liquid such as oil, say to the line L-L, to fill the dashpot chamber 32, after which the tube 26 is hermetically sealed. Thepressure of the gas within the bellows member 25 and the force exertedby the spring 32 together hold the bel lows member expanded with apredetermined force which may be say lbs. per square inch absolute.Surrounding the outer end portion 35 of the stem 3| there is a valveplate member 36 having its marginal edge portion secured and sealed inan internal annular channel 31 in the wall of the casing 11. The stemportion 35 extends through a valve port 38 centrally positioned in andthrough the plate member 36. Cooperable with the port 38 there is avalve member 39 which is screw-threaded on the stem portion 35 foradjustment and which is positioned on the inlet side of the valve port.The inlet or open end of the casing ills-provided with a strainer 40,preferably layers of wire screen mesh of graduated fineness which aresupported by an annular plate 4| seated on an annular internal shoulder42 in the casing IT. The strainer 40 is locked and held in positionagainst the plate 4| by a resiilent bezel ring 43.

The operation of the refrigerating apparatus and compressor with thevalve of Fig. 2 is as follows: When the motor 2 and fan I I are startedin operation for the beginning of a refrigerating cycle, the pressure inthe casing I1 and acting externally on the bellows member 25, will be inexcess of the internal force onthe bellows head member 30 so that thevalve member 39 will be closing its port 38. The compressor operationwill quickly reduce the pressure in the casing I1, so that the pressureof the gas and the force of the spring 34 will move the valve member 39toward open position, thereby admitting refrigerant medium through theport 38 for supply to the compressor. The pressure of the refrigerantmedium on the outlet side of the port 38 and around the bellows memberwill accordingly be held substantially constant, and tendency of thevalve member 39 to chatter or vibrate, due to the reciprocations of thecompressor piston, .will be smoothed out by the action of the dash pot32. When the motor 2 is stopped upon the occurrence of the desired lowevaporator temperature or temperature in the space to be cooled, thepressure of the refrigerant medium in the housing and therefore in thevalve casing I! will increase, thereby moving the Valve member 39 towardclosing position and when the pressure in thecasin l1 and on the suctionside of the compressor l exceeds the force exerted by the pressureresponsive bellows member 25, then the valve member 39 will be seatedand close the port 38 so that the compressor back pressure cannot exceedthe pressure for which the valve 5 is set.

Referring to Fig. 3, the tubular conduit member 4, for connection to thecompressor inlet, carries a cup-like casing 50 at its upper or inletend. The casing 59 ,has a side wall outlet 5| whichis sealed to the endof the conduit member 4. Within the casing 50 there is a pressureresponsive expansible collapsible member 52,

preferably a metal bellows, having head or end wall members 53, 54having their marginal edge portions hermetically sealed to the ends ofthe bellows member. The end wall member 54 has a tubular supportingfitting 55 which is externally screw-threaded to be received in andthrough a nut 56 secured and sealed in a central aperture through thebottom wall 51 of the casing 50. The fitting 55 is provided with aninternal tube 58 through which the bellows member 52 may be evacuated ofair so that temperature change will not vary the internal pressure ofthe member 52. The tube 58 is hermetically sealed, as at 59, after thebellows member 52 has been evacuated of air. Supported and sealed in acentral aperture through the head member 53 there is a valve supportingmember 66 having an internally screw-threaded socket to receive one endof a valve stem 6!. The member 6a is provided within the bellows member52 with a head 62 forming a stop member cooperable with a stop member 63rigidwith the head member 54. The stop members 62, 63 cooperate to limitthe ex pansion of the bellows member 52 under the force of a helicalcoil compression spring 64 which surrounds these members and is heldunder compression between the head members 53, 54. The spring 64 exertsa predetermined expansible force which determines the maximum pressureof the refrigerant medium within the casing 50, and therefore thecompressor back pressure. The valve stem 6| extends through a valve port65 in a valve plate member 66 which is secured and sealed at itsperiphery to the rim or open end portion of the casing 56, as at 61. Thestem 6| carries a valve member 68 positioned on the opposite side of theplate member 66 from the bellows member 52 so that it is movable towardclosed position upon collapse or contraction of the bellows member 52.The operation of this valve and its control of the compressor backpressure will be clear from the foregoing de scription of the apparatusof Fig. 1 and the valve of Fig. 2.

What is claimed and is desired to be secured by Letters Patent of theUnited States is:

l. A pressure limiting valve for controlling the inlet pressure to acompressor,'comprising a cuplike casing having an outlet aperturethrough its end wall, a transverse supporting member in said casing andhaving a central aperture surrounded by fiow ports, a cup-like bellowsend wall member forming a dash pot housing and extending through andsecured in said central aperture and having its base adjacent saidoutlet aperture, a metal bellows member having one end sealed to the rimof said wall member, a head plate member having its periphery sealed tothe other end of said bellows member and having a central opening, avalve port plate member extending across said casing in spaced relationto said head plate member and having a central valve port, a valve stemsecured and sealed in said head plate member central opening and havingone end extending through said valve port and having its other endextending into said dash pot housing, a valve member secured on said onestem end and operable to close said valve port upon contraction of saidbellows member, a piston in said dash pot and secured to said other stemend, liquidin said clash pot, a stop plate member in said casing andhaving an aperture for passage of said stem therethrough, a helical coilspring in said casing and surrounding said stem,.said spring being heldunder compression between said stop plate member and said head platemember, said piston being engageable with said stop plate member tolimit expansion of said bellows member by said spring.

2. A pressure limiting valve for controlling the inlet pressure to acompressor, comprising a cup-like casing having an outlet aperturethrough its end wall, a transverse supporting member in said casing andhaving a central aperture and a flow port therethrough, a cuplikebellows end Wall member forming a dash pot housing and extending throughand secured in said central aperture and having its base adjacent saidoutlet aperture, a metal bellows member having one end sealed to the rimof said wall member, a head plate member having its periphery sealed tothe other end of said bellows member and having a central opening, avalve port plate member extending across said casing in spaced relationto said head plate member and having a central Valve port, a valve stemsecured and sealed in said head plate member central opening and havingone end extending through said valve port and having its other endextending into said dash pot housing, a valve member secured on said onestem end and operable to close said valve port upon contraction of saidbellows member, a piston in said dash pot and secured to said other stemend, a stop plate member in said casing and having an aperture forpassage of said stem therethrough, a helical coil spring in said casingand surrounding said stem, said spring being held under compressionbetween said stop plate member and said head plate member, said pistonbeing engageable with said stop plate member to limit expansion of saidbellows member by said spring.

3. A pressure limiting valve for controlling the inlet pressure to acompressor, comprising a cuplike casing having an outlet aperture, atransverse supporting member in said casing and having a centralaperture, a cup-like bellows end wall member forming a dash pot housingand extending through and secured in said central aperture, a metalbellows member having one end sealed to the rim of said wall member, ahead plate member having its periphery sealed to the other end of saidbellows member, a valve port plate member extending across said casingin spaced relation to said head plate member and having a central valveport, a valve stem secured to said head plate member and having one endextending through said valve port, a valve member secured on said onestem end and operable to close said valve port upon contraction of saidbellows member, a piston supporting stem secured to said head platemember and extending into said dash pot, a piston in said dash pot andsecured to said piston supporting stem, a stop plate member in saidcasing and having an aperture for passage of said piston supporting stemtherethrough, and a helical coil spring in said casing and surroundingsaid piston supporting stem, said spring being held under compressionbetween said stop plate member and said head plate member, said pistonbeing engageable with said stop plate member to limit expansion of saidbellows member by said spring.

EARNEST J. DILLMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 792,757 Cloos June 20, 19051,120,159 Pollard Dec. 8, 1914 1,169,250 Fulton Jan. 25, 1916 1,311,809Giesler July 29, 1919 1,607,657 Whitehead Nov. 23, 1926 1,658,951 StittFeb. 14, 1928 1,931,833 Sparacino Oct. 24, 1933 2,072,617 Cate Mar. 2,1937 2,094,807 Newill Oct. 5, 1937 2,104,700 Russel Jan. 4, 19382,169,554 Buchanan Aug. 15, 1939 2,193,244 Wolcott Mar. 12, 19402,250,362 Dube July 22, 1941 2,357,807 Boynton Sept. 12, 1944 FOREIGNPATENTS Number Country Date 834,242 France Aug. 8, 1938

